Have a 1998 Mitsubishi Diamante…for the past couple of weeks the door locks, the antenna, the blower fan for heating & cooling were working when I first started the car…after approx. 5 mins they would stop…they no longer work at all…thus no AC…in this weather…Phew…took it to mechanic…says he couldn’t find problem…any help would be truly appreciated…as taking it to an electrical place may cost me hundreds of dollars…any ideas?
Check for a corroded or loose ground connection or fault in a fuse box.
Check out fuse 13 in the panel under the hood and make sure that is making good connection. It ties to a junction box which I assume is under the dash. It then ties to a lot of different things and the things you mention having trouble are just part of the list.
This trouble should be pretty easy to pin down with the clues you gave. If the trouble stays bad a good tech should have no trouble finding the problem using a good wiring diagram as a guide and fixed within an hour.